In a semiconductor manufacturing process, there is a case in which a light (radiation) such as, for example, ultraviolet ray, is irradiated to a surface of a substrate. This is performed for the purpose of, for example, modifying the surface of the substrate, heating the substrate, facilitating a chemical reaction in a resist film formed on the surface of the substrate, and removing organic matter existing on the surface of the substrate.
Japanese Patent Laid-Open Publication No. 2009-111050 discloses a substrate processing apparatus configured to irradiate ultraviolet (“UV”) rays to a surface of a substrate. The substrate processing apparatus includes: a substrate holding table configured to hold a substrate that has a resist pattern formed on the surface thereof; a UV lamp positioned above the substrate holding table and configured to irradiate UV lays to the surface of the substrate on the substrate holding table; and a moving mechanism configured to move the substrate holding unit parallel to the UV lamp. The UV lamp is a line light source having a linear shape, and extends to be substantially orthogonal to the moving direction of the substrate holding table. The length of the UV lamp is larger than the width of the substrate in the direction orthogonal to the moving direction of the substrate holding table. Therefore, UV rays are irradiated to the whole surface of the substrate merely by moving the substrate holding table linearly in a predetermined direction below the UV lamp. This is a portion of a processing for smoothing the resist pattern on the surface of the substrate.